Apparatus for moving pipe



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A. L. STONE APPARATUS FOR MOVING PIPE Hmm," O: m. m. oN t omi lm vm INH,O ||l. Immun Il l lm W l r l 1 m. m t o:

May 13, 1952 Filed June l5, 1949 May 13, 1952 A. L. STONE APPARATUS FORMOVING PIPE 2 SHEETS-SHEET 2 Filed June 15, 1949 Yon@ Inventos.

. in .a rapid, .efficient manner.

Patented May 13, 1952 UNITED' STATES APPARATUS FOR MOVING PIPEApplication .l une 13,1949, Serial No. 98,740

13 Claims.

The 'present invention is directed to apparatus adapted for moving andhandling pipe.

The device ofthe present invention is par- -ticularly adapted for use ina derrick for controlling the movement 'of stands of pipe intheAderrick. This device is adapted to be used for controlling the movementof either the upper or lower end of a stand ofpipe having its axissubstantially vertical as the stand-is moved from the :center ofthederrick -to one side of the derrick .andfrom the Nrack tothe center ofthe derrick. The apparatus of the present invention is an improvement.over the apparatusdisclosed in `my copending application U. S. SerialNo. 690,946, led y'August 16, 1946, Yand entitled Apparatus :for MovingPipe, now U. S. Patent 2,537,607,

:issued January 9, 1951. .In the referred to application, the .invention.is Yspecifically directed to the .combinationof thevbase member and anelongated `4member comprising a hook member while the :present inventionis specifically directed vto a combinationof an elongated membercomprising a hook assembly, and a bearing .on

the end of the -hook assembly which cooperates .Withia hinged joint -invthe elongated member :to .provide safety vfeaturesfor causing the hookassembly to unload and release excessive loads 4whichmaybe put onto theassembly such as by failure of 4pipe elevators to vretain .the loadand.to Vrelease the load to .the hook .assembly comprising .the presentinvention.

.Inmany .industrial operations, .it is necessary .tolhandlea great manylengths Aof tubing or pipe As an example of .such .an operation, inthe.drilling of wellsby the rotary drilling method, itis frequentlynecessary vto vWithdraw the entire length of drill stem .fromtheborehole and subsequently replace the drill stem vin the'borehole.`In deep boreholes, many lengths :of vpipe must be .handled in theoperation of withdrawing the drillstem from vthe hole .and in the.operation vof .returning the drill stem Uto the hole. In suchconventional operations,

.it is commento raise the drill stem .so that three =.joints of pipe,Yknown .as .a stand, are above .the surface of .the earth, .to unscrewthe threaded -connection .joining `the lower end of the stand to Athe@remainder ofthe drill stem, then stack the disconnected .stand Ain oneside of the .derrick. It:has heretofore been the practice to station a`manlin 4the .derrick,..called .the derrick man, who Visassigned thetask` of grasping the upperr end of each-stand of vpipe and .controllingthe movement of the upper end when a stand is .being moved over intoracking position. 4It has also 'Z been conventional `for a member of thecrew on the derrick floor to control the movement 'of the lower end ofeach stand yas vit is being placed 'in the rack.

The apparatus .of the present invention .comprises a hook assemblyadapted to engage with ra stand of drill pipe having its axissubstantially vertical when the stand is in the .center of a derrick orwhen .the standhas been racked in a derrick `adjacent other stands ofpipe. The apparatus also includes meansfor extending or retractingthehook along an axis at right 'angles with the axis of the stand of pipelgraspedlbythe equipment. The .apparatus further includes a featurewhich allows the Vhook assembly when subjected to .predeterminedexcessive lloading to dei-lne an arcuate movement which Vactuates apressure releasing means which allows the hook toopen and to release thestand of pipe.

The apparatus .of the present invention spercically includes ra safetybinge vas an integral part of an extensible and retractableihook formoving pipe, whose function .is .to prevent damage to the :hook assembly.and other associated Y equipment byallcwing arcuate movement ofthe hookin the direction of excessive loads while simultaneously releasing thepipe. It will be seen then that the invention particularlyis concernedwith apparatus for moving vertical lengths of pipe and which is providedwith safety features which prevent .damage Lto .the hook by overloading.

vIt is, therefore, the main. object of the present invention to providean 'improved apparatus involving a .safety v.hinge for .moving pipe.

Another vobject of the invention is to provide apparatus including anextensible Land vretractable arm including a hook which embodies a hingemember which will `describe an arcuate movement under excessive loading.

VA still further object of the invention is to provide a hook assemblyfor moving pipe including means for releasing the pipe when the assemblyis excessively loaded.

Still another object of my invention is lto -provide an improvedhydraulic apparatus embodying an varm carrying a hook including ka'hinge member which will describe an arcuate movement under excessiveloading and which will cause release of hydraulic pressure therefrom.

Other objects will become apparent from a reading of the .followingdetailed description taken with .the drawing.

The principal parts of the apparatus of .the present invention are athreaded tubular member I mounted in upwardly projecting housings I2, I3and I4. Attached to threaded member I5 is a hook assembly I6 comprisinga tubular body portion 4I and a hinge 51. The hinge 51 comprises a pin63 and portions 58 and E9 which rotate about pin 55. An importantfeature oi the hinge 61 is a pressure releasing member which may eitherbe a safety valve or a shearable conduit, which will be described inmore detail.

The device of the present invention will now be described in more detailin conjunction with the drawing, in which Fig. 1 is a top elevationshowing an embodi ment of the present invention;

Fig. 2 is an elevation partly in section taken at right angles to theView of Fig. l;

Fig. 3 is a view of the apparatus of Fig. 2 taken along the lineIII-III;

Fig. 4 is a top view partially in section showing the arrangement of thehook;

Fig. 5 is a side view partially in section taken at right angles to Fig.4;

Fig. 6 is a sectional top View of the hinged portion of the apparatus ofthe present invention;

Fig. 'I is a side view in partial section of the apparatus of thepresent invention;

Fig. 8 is a sectional view taken along the lines VIII- VIII of Fig. '7;

Fig. 9 is a sectional View of a preferred embodiment of the hingedportion ofthe apparatus of the present invention;

Fig. 10 is a sectional View of the apparatus of Fig. 9 taken along theline X-X; and

Fig. l1 is agview of the apparatus of Fig. 9 taken along the line XI-XLTurning now specifically to the drawing, and

especially to Fig. 1, plate I I has mounted thereon housings I2, I3 andI4. These housings are adapted to support a threaded tubular member I5.A hook member I6 is mounted on one end of member I5 and astop member I1is mounted on the other end.

. It will be seen that the exterior surface of the major portion ofmember I5 denes a screw thread I8. A keyway I9 extends along theunderside of member I5 parallel with the axis of the tubular member anda central passage 2G extending the full length thereof.

Housing I2 defines a laterally extending opening in which is mounted abushing 2| arranged for embracing the outside surface of square cutthreads YI8 thereby serving to support member I5. Housing I3 issimilarly provided with an opening in which is mounted a bushing 2 I Theinterior of bushing 2l defines keyway 22 having key 23 positionedtherein arranged for slidable engagement with keyway I9 defined bymember I5. In other words, the assembly mounted in housing I2 is adaptedto cooperate with the outer surfaces defined by thread I8 to support rodmember I5 and with the key 23 to prevent rotation of member I5. Y

The housing I4 is positioned between housings I2 and I3 and serves asthe mounting means for an assembly adapted to move rod member i5longitudinally. Housing I4 isv bored of a diameter such that it willreceive a bearing assembly comprising ball races 24 and 25 and bearings21.

A member 28 of a generally tubular shape and having its interiorthreaded to mate with threads I8 `is mounted for rotation in the housingI4. Member 28 defines a surface 29 which makes a sliding fit in ballrace 24 and is provided with threads on which is screwed ring 30 whichcontacts with ball race 24 and a second ring 3I Y hook I5 toward thebase plate.

which acts as a lock ring. Entry of foreign materials into the bearingassembly is prevented by closure 32 which is positioned between housingI4 and member 28 and closure 33 which is positioned between member 28and cover plate 34. The end of member 28 adjacent closure 32 extendsoutside the closure and has the configuration of a pulley with a groove35 which provides the driving surface, for example, with a conventionalV-shape belt.

It will be seen that by providing a suitable rotating means for member28, it may be rotated in one direction which will cause the hook I5 ofthe member I5 to Ibe moved away from the base plate and in the oppositedirection to withdraw The movement of member i5 is limited in onedirection by contact of shoulder 4) with bushing 2| and in the oppositedirection by contact of stop member I1 with bushing 2|. A

Hook member IS comprises a body 4I having a generally 4annular shapeadapted to be secured to the end ofA tubular member I5 and having abifurcated portion dening members 42 and 43. It will be understood thatmember I6 may be attached to body 4I in any suitable manner. In thedrawing, member I6 is shown as attached to body 4I by screw threads 44and is retained in position by a lock nut 45.

Arranged within the recess formed by the bifurcated section of member I5are crosshead member 49, link 41, and jaw member 48 connected by pins 45to form a linkage allowing jaw member 48 to move arcuately about pin 49awith lineal movement of crosshead member 49.

Crosshead piece 49 is encircled by spring member 58 and may be actuatedagainst the spring by hydraulic iiuid in a manner which will bedescribed.v As hydraulic iiuid is introduced into the central passage 20which extends the length of member I5, spring 50 is compressed as willbe described and member 45 bears against link 41 causing jaw member 48to be moved about the pin 49a by a crank action motion and thus causingthe hook or jaw4 member 48 to be moved inwardly toward member 43 causinga stand of pipe to be enclosed and grasped by member 48 and member 43.Similarly, release of hydraulic fluid from passage 2l) releases theforce exerted on spring 50 which causes the hook or jaw member 48 tomove outwardly in the open position as shown by the dotted lines. Jawmember 48 retracts into a cover member 5I which is designed as a safetyguard to prevent damage to personnel when it projects from the enclosuredefined by member 42.

Arranged on the end of member 48 is a roller 52 which is held in placeby a pin 53 resting on a shoulder 54. Pin 53 may be externally threadedto engage with internal threads in bushing 55 to allow roller 52 to besecured thereto. Roller 52 is designed to rotate freely on pin 53 as atangential force is exerted against it. Thus, when a stand grasped bythe hook is raised or lowered they roller 52 rotates and substantiallyreduces the force on the hook due to friction, thereby preventing anormal operating force from acting on the safety hinge. This feature isimportant in'preventing damage to the hook assembly by sudden loadingdue to dropping a stand of pipe and exerting a force against member I6.This feature is also important in combination with other necessaryfeatures of my apparatus which will be described in more detailhereinafter.

T55 I V`ll'll;cnil-rer M "is providedfwith-"setrsorews @5S/andFisidesgnedsoithatiitmaylbe arrangedasffshown "in Tig. 4or^"moved"inwardly Tas'shown-by f'the dttdilines inTig. "4 to"l include1ay smaller "space than. that shown .by the full lines. Thus, byma- .1

'n'ipulation of v'set vscrewsl itmay be possible 5to widen vornarrow""the 'enclosure rkf'd'eilned "by "jaw members 42 and "'43 'tto'accommodate 5Vlarger or .smaller stands 'of'gp'ip'e as required.

`Re`ferring now to 'Figures l4 and "6 it `will be lseen'that""bodymember '41 is connectedto Lhook by I'threads 44 and A"tubular "memberJ'IS by rthreaded connection '51. LBodymember aIl] is of 'tubular.structure `and 5 denes .a chamber '-58 in whihiis 5 arranged a"sleevefq"whichl` intum de- "fines arst chamber "6U in 'which Jis"arranged crossheadlpiece "49 and` spring"50. 'Sleeve 5.9 also denes asecond chamber IBI which "is Aopento 'chamber 'S58 fand arranged"therein is A'a piston v.member T52 whic'hlprojects -into chamber B0"and .bears friictionally :against .crosshead piece 'll-'9. iPiston.member 152 comprisesa pack oit ring 63 'ltopreverit passage ofvhydrauli'c'llnid around. the piston and Yto allow pressuretobeexertedJagainst npiston 4$2. Sleeve 59 is also provided with packing59a lto VA'insure a seal.

.It willibe apparent that'cha'mber is'in Liiu'id .communication withpassageway "6l defined by vtbular body member Il 'which 'in "turn'fiu'dly communicates with a vertical passageway 65 de- Yflnedby pin-66..Passageway "65 'is closedby a set `screw 65a. 'Tubular body member-llis con- Ystructedto de'nea hinge '61 whichpivotsaround pin BB .inamanner which will be described.

'ines a `recess 8l toziacoommodatea'sphereir.l rwhen ReferringthowtoLitige-'.7 .and i8 :itfwill be f that hinge portion '169 'denesitlnee :chambers each housngfa @spring $9 runder -zpompressio'n .Hinge`61 vis deiinedby portion' oi body mem--` 'ber '4I whic'hdenespassageway andportion `69 which .includes threadedconnection 51 andshoulder 4.0. 'Portion .69 dfinies a passageway "10 whichjis in fluidcommunication with .central passageway, vertical passageway 65. and`thus with passageway 64 and chamber 58 and "61. "It .willbe immediatelyapparent 'that "introduction of aliydraulic iiuid into passageway 20will cause pressure '.to 'be exerted against piston "62 and vthenceagainst crosshead vpiece 49 arranged lin '545i sleeve 59 and in turnwill actuate lthe hook assembly vrI6 as has been described;

Pin 66 'inhnge 61 is secured by a lock 'nut '1I which rests on va washer'1.2 which in turn 'eny gages with aspring 'I3 and exerts"force-:against thehinge B1. lPin 66 protrudes through lliinge B1 anddenes a shoulder'lfd .that 'bears fric- .Itionally against a .second.spring .member which serves tohold portions '68 land "6'9 oi body.member .4l defining thehinge 61. .Pin .66 also ,de'nes'lateralpassageways'ls and '11 communieating, respectively, with jpassagewaysilland'll .and .also with passagewayV l8r, -the 'latterlpassagewaylterniinating .in `a chamber I9 dned "by portion "G9 off'hinge .61."Passageway `64 "is provided with fa partial ring -groovefla extending.`1-8D..so that fluid maybe released 'rom,passage ways T65 .and `B4 inrotation ofojportion 68 as will lbe described nfurther. "From'thefforegoing descriptiontaken with the drawing, central passage.andpassageway'l 'define Va 'rstpassageway passagewayt and chamber*58define 'a second passageway, 'and' pin 63 denes athird'passage- /way^65.l"Thepin also de'nes passageways 16 'and FL-the ff'ormer beingpart'oithe asecond-passageway and `serving 'to `communicate with thethird passageway while 'the "-latter forms Lpartof Athe first passagewayand serves 'topommunicate 'withltheithirdpassageway.

wi-iieh is :resisted@infonefdirectionbyisetfscrewr permittingadjustment, hand in fthe opposte-'ditraction by fplug 150 which '.bearsra'gainst'itapered hole 119811 y 4defined by v'hafrdened plate' 5&6.IY-he mechanism v2in '-'lthe three chambers enbodies ea locking "devicewhichv servesftomaintaintth'ehinge 61'," member v155fandnmik f6'inlongitudinalfalglvment V'erop-epi', under conditions 'of excessivev4loacl- Jing .of hook "Ther-plug 90lbearsragainstplate "'86 'and serves-to resist rotation offtheplate 86 in a downward direction.

Por-tion 6810i hinge 61 fand-hardened'iplate f fdene aligning holes F91which flcontai-n'zpins .i9 la 1 to prevent vmelative 'rotation betweenthese A:two

members.

As the "portion '6810i hinge 'i617 fan'dhardened plate'rotate'-with-respectto po1tion"69=of-hinge 617, vplug F93 -is forcedyag-ainst'sprin'g189 as the tapered hol-es inlplatelbecome"misalignedhus 'crea-ting a resistance f-itoinitialrelativerotation between portions i158 and i6-9 of -hinge B1.

Simultaneously with the -a'ioreinentioned "action tapered'1hole58'lof?hardenedplate'iuecomes misaligned with chamber 19 causingvfsplfi-erical 'body 581| Ato tmove 'against Vspherical body. 80 andacompress vspring 132 thereby releasing hydraulic lhuid 4"frompassageway 65 vthrough Ythe :resulting :opening in chamber 19. Thisremoves force v `against crosshea'd member .i9 @and spring' -movesl'this linkage Iand V'thus opening jaw rn'embert.

y It will be apparent that, pin slslprovidedwith packing ringsa2'1to-provi`de1aseal.

lRse'ierring vnow to "Figures 9, `1v`0,"an"d 111, alpreyferredembodiment of 'the hinge flilwillflbe 1deyscribedin which a simplermeans'thanfthefsafety 'valve including spherical bodies :willbedescribed.

lnf'this embodiment, it will be fapparentthat'ohe A"hinge 61`is-eonstructetl offatop section i160 and .abottom section 'ml, each ofwhich'is provided 2with I-a projecting Atia-nge 'portion S1192 vdeiining-passageways H23 sand l f ull. Arranged in'passagefW-ay 'ID3 'is "lashear Apin W5 and arranged passageway 'Hill iis `'a `sl'iearable'conduit 106i Shearable conduit 406 'is connected to passageway Zll by ascrew plug connection -I-lll and in "turn is connected to passageway 265."inpin 66 by "a screw plug connection l08. Thus, she-arable fcondui-tv'I {i6-connects -passageway'with passageway 65 fand replaces the safetyva'lvlefin .the'porftion 69 of the 'embodiment j:of Figure-i6. Itzwilllbe obvious -that the lernlo'o'dimentfof i 9,

L10, :and 'l1 fsimpler A-to `construct and Imaintain lithan theaembodiment .of Fgme Grand ...fewer `operating' parts, and, :thereforeisimore eiii'cient kithanfthe embodimentof :Figure rv6.

In operating the apparatus of the present sinfvention hydraulic .iluidlmay lb-e .introthxcedfinto central passageway 2u 'from :a .sourceA'shrmvn through 'flexible conduit .H0 connecting :memz:ber 'P5 tof:a=source of fluidiunderrpressure. Vilon- Jduiit 'flzl' '.mayibesecuredto member 3.!5 by amou- Arranged in i chamber i118 'iis a wal-vevmember 75 fplingoriunion:LH .tormake apressure tiglrtaconving piston 62and crosspiece member 4S.

nection. As the hydraulic fluid is introduced into passageway 20 itflows therethrough and thence into passageways 7U, 65, 64 and finallyinto chambers 58 and 6| where its pressure is exerted against piston 62which is forced against crosshead piece 4s. Crosshead piece 49 in movingforward compresses spring 50 and actuates jaw member 48 through pins 46and link 41 by a crank action motion well understood by the skilledworkman. This causes jaw member 48 to move inwardly and embrace a standof pipe which may be moved into position or engaged by movement of theassembly l5 carrying the hook assembly I6. If the stand of pipe embracedby the jaw member 48 should suddenly load the hook member I5, the roller52 on the end of jaw member 48 -would rotate minimizing frictional drag.At the same time the vertical loading of the assembly Awould cause anarcuate movement of portion 68 of hinge 61 about pin 66 which wouldcause release of hydraulic fluid in the device of Figures 6 and 7through the spaces between portions 68 and 69 thereof or would causerelease of fluid by shearing pin H and conduit IUS in the preferredembodiment of Figures 9, 10, and 11. The release of fluid in the devicesof Figures 6, '7, and 8 is accomplished by arcuate movement of the hinge61 about pin 66. As hinge portion 68 rotates downwardly with respect toportion 69 the plate 86 also rotates moving the sphere 8| downwardagainst sphere 86 opening the chamber 79 to the atmosphere through thespaces shown between portions 68 and B9 and thus causing release ofiiuid from the iirst passageway to the third passageway and from thesecond to the third passageway which allows the spring 5B to move piston62 to the left and thus opening jaw member 48 which releases the load.As the fluid pressure is released the jaw member 48 would be retractedinto an open position by release of pressure on spring 50 as pressure isrelaxed on crosshead piece 49, thus allowing the stand of pipe to bedropped without causing damage to the hook assembly.

In operating the apparatus of the present invention hydraulic fluid maybe introduced into central passageway 25 by means of a conduit l lilconnecting member l5 to a source of hydraulic fluid under pressure.Conduit HD may be secured to member V5 by :a coupling or union Ill tomake a. pressure tight connection. As the hydraulic p-ressure isintroduced into the passage it flows therethrough and thence intovertical or perpendicular passage 65 dened by the pin 56 and thence intothe chamber 60 enclos- The hydraulic pressure exerted against piston 62and cross piece 49 causes springs 5i) to be compressed and, through pins46 and link 41 by a crank action motion which will be well understood bythe skilled workman, causes jaw member 48 to be moved inwardly toenclose a stand of pipe which may be moved into position or engaged bymovement of the assembly I5. It will be seen, therefore, that thecombination of the elongated member, the hook assembly, the rollerbearing, the hinged joint and the pressure releasing means cooperate toprovide a safety feature of the apparatus of my invention.

g.. The hydraulic iiuid employed in my apparatus may be either a liquidor gaseous uid. For example, a highly rened hydrocarbon oil in thelubricating oil boiling range may be employed as hydraulic iluid.Alternatively, the hydraulic fluid may be a gaseous material such ascompressed Y air;in fact, compressed air may be desirable since suddenrelease of a liquid such as hydrocarbon oil may dump oil on workmenworking adjacent to cr below the assembly -of the present invention.

The nature and Vobjects of the present invention having been completelydescribed and illustrated, what I wish to claim as new and useful andsecure by Letters Patent is:

1. Apparatus for grasping and moving pipe comprisingin combination, abase member and a retractive member having a free end, said base memberbeing adapted to support said retractive member, a hook member on thefree end of said retractive member, said hook member deiining a hingeadapted to define an arcuate movement about an axis perpendicular tothat of said vretractive member on operation thereof, said retractivemember deiining a passageway operably communicating with and adapted todeliver fluid Apressure to said hook member, and a pressure releasingmeans fluidly communicating with said passageway adapted to be actuatedby and to release fluid pressure on arcuate movement of said hinge.

2. A device in accordance with claim 1 in which the pressure releasingmeans is a valve.

3. A device in accordance with claim 1 in which the pressure releasingmeans is a shearable conof said elongated member, a Erst element xedwith respect to the tubular member defining a iirst end with the surfacethereof substantially parallel with the axis of the tubular member andlaterally displaced away from the outer surface of said tubular member,a movable member mounted for arcuate movement about an axisperpendicular .to that of the tubular member and having a second endadapted to be moved toward and away from said first end, a hinged jointin said tubular member deiining a third passageway fluidly communicatingwith rst and second passageways, and pressure releasing means iiuidlycommunicating with said third passageway.

5. A device in accordance with claim 4 in which the pressure releasingmeans is a valve.

6. A device in accordance with claim 4 in which the pressure releasingmeans is a shearable conduit.

7. A device adapted for grasping and releasing an object having acylindrical surface comprising, in combination, an elongated memberdefining a first passageway, a hook assembly comprising a tubular memberdelining a second passageway, said hook assembly being mounted on a freeend of said elongated member, a first element xed with respect to thetubular member dening a iirst end with the surface thereof substantiallyparallel with the axis of the tubular memberV and laterally displacedaway from the outer surface of said elongated member, a movable membermounted for arcuate movement about an axis perpendicular to that of thetubular member and having a second end adapted to be movedtoward andaway from said rst end, a hinged joint arranged in said hook assemblydening a third passageway iiuidly communicating with said first andsecond passageways, and a valve in said elongated member positionedadjacent to and in communication with said third passageway and anexterior surface of said hook assembly and operative by arcuate movementof said hinged joint.

8. A device adapted for grasping and releasing an object having acylindrical surface comprising, in combination, an elongated memberdefining a first passageway, a hook assembly comprising a tubular memberdefining a second passageway, said hook assembly being mounted on a freeend of said elongated member, a first element fixed with respect to thetubular member defining a first end with the surface thereofsubstantially parallel with the axis of the tubulai member and laterallydisplaced from the outer surface of said tubular member, a movablemember mounted for arcuate movement about an axis perpendicular to thatof the elongated member and having a second end adapted to be movedtoward and away from said first end, a hinged joint arranged in saidhook assembly defining a third passageway fluidly connected with saidfirst and second passageways and a valve assembly iiuidly connected withsaid third passageway and an exterior surface of said hook assembly andactuated by arcuate movement of said joint.

9. A device adapted for grasping and releasing an object having acylindrical surface comprising, in combination, an elongated memberdefining a first passageway, a hook assembly comprising a tubular memberdefining a second passageway, said hook assembly being mounted on a freeend of said elongated member, a first element fixed with respect to thetubular member defining a first end with the surface thereofsubstantially parallel with the axis of the tubular member and laterallydisplaced away from the outer surface of said tubular member, a movablemember mounted for arcuate movement about an axis perpendicular to thatof the tubular member and having a second end adapted to be moved towardand away from said first end, a pin in said elongated member defining athird passageway perpendicular to and fiuidly communicating with saidfirst and second passageways, a hinged joint defining slidable surfacespivotally movable about said pin, and pressure releasing means fiuidlycommunicating with said third passageway.

10. A device in accordance with claim 9 in which the pressure releasingmeans is a valve.

11. A device in accordance with claim 9 in which the pressure releasingmeans is a shearable conduit.

12. A device adapted for grasping and releasing an object having acylindrical surface comprising, in combination, an elongated memberdefining a first passageway, a hook assembly comprising a tubular memberdefining a second passageway, said hook assembly being mounted 60 on afree end of said elongated member, a first element fixed with respect tothe tubular memfirst and third passageway.

10 ber dening a first end with the surface thereof substantiallyparallel with the axis of the tubular member and laterally displacedaway from the outer surface of said tubular member, a movable membermounted for arcuate movement about an axis perpendicular to that of thetubular member and having a second end adapted to be moved toward andaway from said first end, a roller bearing mounted on said second end, apin in said elongated member defining a third passageway perpendicularto and fluidly communicating with said first and second passageways, ahinged joint dening slidable surfaces pivotally movable about said pin,and a valve arranged adjacent to and fluidly communicating with saidthird passageway and an exterior surface of said hook assembly andoperative by arcuate movement of said hinged joint.

13. A device adapted for grasping and releasing an object having acylindrica1 surface comprising, in combination, an elongated memberdefinin'g a first passageway, a hook assembly comprising a tubularmember defining a second passageway, said hook assembly being mounted ona free end of said tubular member, a first element fixed with respect tothe tubular member defining a first end with the surface thereofsubstantially parallel with the axis of the tubular member and laterallydisplaced away from the outer surface of said elongated member, amovable member mounted for arcuate movement about an axis perpendicularto that of the tubular member and having a second end adapted to bemoved toward and away from said first end, a roller bearing mounted onsaid second end, a pin in said elongated member defining a thirdpassageway perpendicular to and fiuidly communicating with said secondpassageway, a hinged joint defining slidable surfaces pivotally movableabout said pin, means to exert tension against said hinged joint and tomaintain said slidable surfaces in frictional relationship to eachother, a flange member arranged on the exterior of said hinged joint anddefining passageways adapted to receive a shear pin and a conduit, ashear pin arranged in one of said passageways in said fiange member anda shearable conduit i cans arranged in another of said passageways insaid iiange member defining a pressure releasing mean-s fiuidlycommunicating with said ALBERT L. STONE.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 2,162,653 Umphres June 13,19392,290,247 Perkins July 21, 1942

